IH CALIBRATION STANDARDS

INTERWOOLLABS’ activities have been crowned by official recognition from the International Wool Textile Organisation of its IH calibration standards as official I.W.T.O. calibration standards for Air-Flow, Projection Microscope, Laserscan and O.F.D.A. measurement apparatus.

The first series was established in 1972. It was the result of the most extensive testing and retesting that significant quantities of standard wool tops have been established. Limited to a maximum duration of 3 years, this series has replaced by seventeen further series, each of them having been valid for a period progressively reduced to 2 years. The 23rd Series will be valid until 31 January 2022, with respective finenesses as follows:

25th SERIES OF IH-STANDARDS (Valid: 01.02.2024 – 31.01.2026)

Standard Values to be used for the calibration of the Instruments for the fibre diameter measurements

STANDARD VALUES

Standard No.	Mean fibre diameter (µm)	Mean fibre diameter (µm)	Distribution of fibre diameter (CV %)	Fibre Curvature (deg/mm)
1 PM	not applicable	14.58	17.93	84
1 AF	17.64	not applicable	not applicable	not applicable
2	18.86	18.73	18.89	69
3	21.39	21.35	19.04	64
4	23.48	23.51	19.75	59
5	27.87	27.98	22.00	59
6	30.63	30.61	22.86	53
7	32.85	33.34	25.87	56
8	36.80	36.83	21.72	39

Eight Tops are required to calibrate Airflow (IWTO-6), Laserscan (IWTO-12) and OFDA (IWTO-47).

To calibrate Airflow Instruments, tops “1AF” and “2” to “8” only shall be used.
To calibrate Laserscan and OFDA instruments, tops “1PM” and “2” to “8” shall be used. Do not use top “1AF”.

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